Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Nat Commun. 2014 Jun 17;5:4090. doi: 10.1038/ncomms5090.
The a priori ability to design electromagnetic wave propagation is crucial for the development of novel metamaterials. Incorporating plasmonic building blocks is of particular interest due to their ability to confine visible light. Here we explore the use of anisotropy in nanoscale and mesoscale plasmonic array architectures to produce noble metal-based metamaterials with unusual optical properties. We find that the combination of nanoscale and mesoscale anisotropy leads to rich opportunities for metamaterials throughout the visible and near-infrared. The low volume fraction (<5%) plasmonic metamaterials explored herein exhibit birefringence, a skin depth approaching that of pure metals for selected wavelengths, and directionally confined waves similar to those found in optical fibres. These data provide design principles with which the electromagnetic behaviour of plasmonic metamaterials can be tailored using high aspect ratio nanostructures that are accessible via a variety of synthesis and assembly methods.
预先设计电磁波传播的能力对于新型超材料的发展至关重要。由于等离子体激元结构能够限制可见光，因此特别关注将其纳入其中。在这里，我们探索了在纳米级和中尺度等离子体阵列结构中引入各向异性，以产生具有不寻常光学性质的基于贵金属的超材料。我们发现，纳米级和中尺度各向异性的结合为整个可见光和近红外区域的超材料提供了丰富的机会。本文所探索的低体积分数（<5%）等离子体超材料表现出双折射现象，在选定波长下，其趋肤深度接近纯金属，并且具有类似于光纤中发现的定向限制波。这些数据提供了设计原理，可以使用通过各种合成和组装方法可获得的高纵横比纳米结构来调整等离子体超材料的电磁行为。
